1. Field of the Invention
The present invention relates to a solid-state imaging device, a method for processing a signal of the solid-state imaging device, and an imaging apparatus.
2. Description of the Related Art
In order to increase the sensitivity of solid-state imaging devices, a plurality of techniques in terms of a color filter array and signal processing of the color filter array have been developed (refer to, for example, Japanese Unexamined Patent Application Publication No. 2007-287891). One of the color filter arrays is a color filter array that uses a color (e.g., white (W)) serving as a primary component of a luminance signal. As color coding using a white color, white checkerboard color coding in which white is arranged in a checkerboard pattern is frequently used.
The output voltage of a color filter array using a white color is higher than that of a color filter array having an RGB Bayer arrangement that has been widely used. Accordingly, the sensitivity of a solid-state imaging device can be increased. Note that, in the RGB Bayer arrangement, green (G) is arranged in a checkerboard pattern. Red (R) and blue (B) are also arranged in a checkerboard pattern in the other area of the checkerboard pattern.
In solid-state imaging apparatuses using a color filter of an RGB Bayer arrangement, in order to convert an RGB signal into a YUV signal (Y: a luminance signal, U and V: color difference signals), computation for generating a Y signal is necessary. In the computation, for example, the following equation can be used:Y=0.29891×R+0.58661×G+0.11448×B
In general, this computation is performed by a digital signal processor (DSP) provided outside a substrate (a sensor chip) of the solid-state imaging apparatus. Accordingly, even in the solid-state imaging devices using a color filter array including a white color, computation for generating a luminance signal Y is performed by a DSP provided outside a sensor chip.